We present an analysis of a Chandra observation of the massive , nearby galaxy cluster Abell 2319 .
A sharp surface brightness discontinuity—suggested by previous , lower angular resolution X-ray imaging—is clearly visible in the ACIS image .
This \sim 300 kpc feature suggests that a major merger is taking place with a significant velocity component perpendicular to the line of sight .
The cluster emission-weighted mean temperature is 11.8 \pm 0.6 { keV } , somewhat higher than previous temperature measurements .
The Chandra temperature map of A2319 reveals substructure resembling that anticipated based on hydrodynamic simulations of cluster mergers , and shows an associated cool core not previously known .
The map shows a separation between the intracluster medium ( ICM ) and galaxies of one subcluster , indicating a transient state in which the ICM has been stripped from the subcluster galaxies ( and presumably the dark matter ) .
Detailed analysis of the merger feature shows a pressure change across the surface brightness discontinuity by a factor of \lesssim 2.5 .
The higher density side of the front has a lower temperature , suggesting the presence of a cold front similar to those in many other merging clusters .
The velocity of the front is roughly sonic .

We compare bulk properties of the ICM and galaxies in A2319 to the same properties in a large sample of clusters as a way of gauging the effects of the major merger .
Interestingly , by comparing A2319 to a sample of 44 clusters studied with the ROSAT PSPC we find that the X-ray luminosity , isophotal size , and ICM mass are consistent with the expected values for a cluster of its temperature ; in addition , the K -band galaxy light is consistent with the light–temperature scaling relation derived from a sample of \sim 100 clusters studied with 2MASS .
Together , these results indicate either that the merger in A2319 has not been effective at altering the bulk properties of the cluster , or that there are large but correlated displacements in luminosity , isophotal size , ICM mass , galaxy light , and emission-weighted mean temperature in this cluster .